https://www.youtube.com/watch?v=x79l7UO_qww
Caveat: The bike used is an e-bike with a powered wheel. The pedals have very little load requirements and no long-term or load testing is shown. As one of the most hardcore roadies you'll ever interact with, personally, I believe this would not last more than a week if it could survive a single ride on a traditional bike and someone like myself based on my first impression of the design. Still, the idea is impressive to me. In practice, a robust enough design will likely outweigh a chain drive by an order of magnitude. The reason the chain and cog transmission is standard is because of the balance of weight to durability. Every single gram matters on a bicycle far more than may be apparent at first.
The positives of a belt drive are maintenance, and that it stays clean so they are most popular with commuters that do not want a dirty pants leg or newbie chain tat. They are only common on heavier bikes like short haul commuters in general and require a "broken frame" that is designed for them in the first place. The lack of transmission gearing means you need to either know exactly what gear ratio you need and deal with only having one speed or you need an internally geared hub. All internally geared hubs have monstrous weight to add. So in practice, you do not find many of these on the market. Even with an e-bike, you still need a geared transmission unless you have throttle control without pedaling.
On the other hand, for a hipster roadie, a fixie with a belt drive is some serious cred. Especially if they can dish it at the local group ride against people on flagship bikes.
Yeah, no lubricants and the look / style factor - that was my conclusion as well.
As for maintenance, while a belt might last 3 times as long, that's not really a factor, given the price difference between belts and chains.